In this code block how many fields of being validated?

<form id="form1" runat="server">
            <h1>401K Future Value Calculator</h1>
            <label>Monthly investment:</label>
            <asp:DropDownList ID="ddlMonthlyInvestment" runat="server" CssClass="entry"><br />
            <label>Annual interest rate:</label>
            <asp:TextBox ID="txtInterestRate" runat="server" CssClass="entry">6.0
                <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
                    CssClass="validator" ErrorMessage="Interest rate is required." 
                    ControlToValidate="txtInterestRate" Display="Dynamic" Enabled="False">
                <asp:RangeValidator ID="RangeValidator1" runat="server" CssClass="validator" 
                    ControlToValidate="txtInterestRate" Display="Dynamic" 
                    ErrorMessage="Interest rate must range from 1 to 20." MaximumValue="20" 
                    MinimumValue="1" Type="Double" Enabled="False"><br />
            <label>Number of years:</label>
            <asp:TextBox ID="txtYears" runat="server" CssClass="entry">10
                <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" 
                    CssClass="validator" ControlToValidate="txtYears" Display="Dynamic" 
                    ErrorMessage="Number of years is required.">
                <asp:RangeValidator ID="RangeValidator2" runat="server" CssClass="validator"
                    ControlToValidate="txtYears" Display="Dynamic" 
                    ErrorMessage="Years must range from 1 to 45." MaximumValue="45" 
                    MinimumValue="1" Type="Integer" Enabled="False"><br />
            <label>Future value:</label>
            <asp:Label ID="lblFutureValue" runat="server" Text=""><br />
            <asp:Button ID="btnCalculate" runat="server" Text="Calculate" CssClass="button" />
            <asp:Button ID="btnClear" runat="server" Text="Clear" CssClass="button" CausesValidation="False" />
        </form>